In medical engineering, in particular in the field of radiology, data processing networks are operated in an alternating manner by different users. Generally each user requiring access to a data processing facility has to log in to the facility by inputting a user name and a password at a work station. After logging in successfully the users starts a workflow, e.g. to process and evaluate image data, with one or more application programs, hereafter referred to simply as applications, being called up and used. Such an application comprises a plurality of functions, with different classifications with a view to enhanced security, so that only users with higher authorization levels can execute certain functions. It may therefore be that to carry out some application-related actions, e.g. to execute different applications or different functions of an application, an additional user identification is frequently required for security reasons, it being necessary for example to input a further password. However this procedure takes more time and is associated with a major mental effort for the user, as the user has to remember a number of passwords needed for the individual application functions.